DDNS uses a particular domain to associate with the IP address of the device and the DDNS service polls that domain periodically. If you whitelist the domain that the service polls, your DNS won't appear to change to that domain.

The domain to whitelist is likely the same as what you enter into your device's DDNS Client Settings, such as dyn.com or noip.com. To whitelist the domain, visit http://my.winstonprivacy.com/allowed .